Telephones have proven to be very adept at invading the privacy of the person being called (herein the "user" or the "called party"). A particularly annoying technique is that of salesmen calling during the dinner hour to sell some dubiously useful device. In addition, wrong numbers have become more prevalent as more and more people need telephones, and the telephone company is forced to reassign more quickly those numbers which have been previously used.
It is an object of the present invention to circumvent nuisance telephone calls. For purposes of the invention, desired calls are those that the called party wants to receive, and nuisance calls are those that the called party does not want to receive. These nuisance telephone calls can be both of an incidental nature and of an intentional nature. Incidental nuisance calls are those resulting from dialing the wrong number, either through mistake or by using an outdated number. Intentional nuisance calls are those which result from telephone solicitation, private telephone calls from business acquaintances, telephone calls from people whom the called party does not want to talk with, or so-called obscene telephone calls which have the object of intimidating or harassing the called party.
There have been several attempts to mitigate nuisance telephone calls. The technique most prevalently used is to obtain an unlisted telephone number. This has a certain mitigating effect as it makes it a little harder for someone to find a particular telephone number. However, this method has certain disadvantages and only limited usefulness.
Unlisted numbers have associated fees charged by the telephone companies. The telephone company charges both a one-time fee and a monthly fee for allowing the user the privilege of having his phone number unlisted. Another disadvantage is that the intended use of a telephone is somewhat defeated by having an unlisted telephone number. If the number is unlisted, many desired calls may be missed, because someone you may want to talk to may never be able to get your number.
Moreover, the telephone number, even if unlisted, will still eventually get to salesman-type callers. Through normal usage, the telephone number will eventually get out to many parties. Certain items such as credit applications and the like will always be sources for telephone numbers. By giving this access to one's telephone number, it will eventually get sold to telephone solicitation agencies, thus ruining whatever privacy one once had. The only real solution has been to change the number, and making sure all your friends, relatives, etc., get the new one. Those that do not will be unable to call.
Another method which has been more recently used for mitigating unwanted telephone calls is to use the telephone answering device as a call screening device. The disadvantage of this method is that the subscriber must be disturbed by the ringing for each incoming call. The subscriber must go near the answering machine, to determine if the person calling is someone who the subscriber needs or wants to talk to. If the call is of an urgent nature, or from a desired calling party, it may be missed if this technique is used. Moreover, some people have a phobia of answering machines, and refuse to leave messages and just hang up.
A third technique is a call tracing method. Some telephone companies offer a service which allows each call to be automatically traced and have the number of the caller displayed to the subscriber. If the call turns out to be a malicious call, the telephone number of the calling party is known. However, for purposes of screening calls, this method is of limited usefulness. The subscriber may recognize certain telephone numbers and know that he wants to answer when these telephone numbers are calling. However, this technique requires the subscriber to have a large memory to recognize every telephone number which is calling. In addition, there is a substantial monthly charge for this service. Finally, this method has the same disadvantage as the telephone answering machine method--it requires the user's peace and quiet to be disturbed each time a telephone call comes.
The present invention addresses this need in the art by providing a device which obviates all of these problems. The present invention defines a device which is intended in its preferred embodiment to operate in conjunction with an answering machine. In operation, the user turns off all ringers on the phones in his house. The device routes calls between one of two actions. Either the call will operate the answering machine and the user will enter a message on the answering machine, or else, if the caller has the predetermined and secret code, the call will be routed to some external and auxiliary ringers located in the user's home.
If the caller does not have the predetermined code, the ringers in the user's home are not activated, and the caller's only option is to leave a message. This enables the caller to leave a message for the user, obviating the problem of unlisted telephone numbers. If the code becomes too well known, it can be changed, and the worst that happens is that a desired caller leaves a message the first time that they call after the code is changed. However, if the caller has the predetermined code, the caller can cause the ringer in the user's home to be operated.
The preferred embodiment of the device operates in conjunction with a standard telephone answering machine. The answering machine answers the telephone in the usual way, and the message on the answering machine is an instructional message to the user on how to operate the device. If the user has the predetermined code, it must be entered before the time-out period of the answering machine is over. If the code is entered, the telephone line is seized for a predetermined period of time by the present invention which also initiates a ringing tone within the user's home for this predetermined period.
According to other preferred aspects of the invention, various techniques are also used to insure proper operation of the device. Since the device is operated using touch-tone characters, it would be possible to initiate the device inadvertently during calling out by a random sequence inadvertently matching the predetermined code. In order to guard against this possibility, the present invention uses an exclusion character as part of the code. The exclusion code is a code intended never to occur in a called-out number. Similarly, the code of the present invention must be received in proper synchronization in order to avoid a user trying all possibilities to get through eventually. In order to do this, the invention also uses an initialization character as one element of the code, and this initialization character is one which is not used in any secret code.
Various methods have been attempted in the art to meet the objective of the present invention, but all of them have had serious drawbacks which have prevented user acceptance of these devices.
U.S. Pat. No. 4,387,272 to Castro has a similar objective to the present invention. Castro desires to decide whether or not the calling party is a desired one, and to send all nuisance calls to the answering machine. In order to do this, Castro receives each telephone call, and then waits for a pre-established code after having sent a ringback signal. If the code is not received after a predetermined time, the telephone line is connected to an answering machine. The answering machine only answers after it is decided that the code will not be coming. If the code is received, it is displayed and an acoustic signal source is activated.
Castro, however, has many drawbacks. First of all, the system is extremely complicated because of its basic inherent design. Castro requires much interface with the telephone answering machine. If it is decided that the call should be routed to the answering machine, Castro must somehow turn on the answering machine to record the call. This means that Castro would either have to use a specially designed answering machine, or produce tones or the like to turn on the answering machine somehow. Castro describes in column 8 beginning at line 25 how it must send the answering machine a signal similar to those of a telephone call so that the machine can "answer".
Another drawback of Castro is that the user gets no instruction on what to do upon the call connect. Castro sends a ringback tone, but if the user does not know what to do he may not enter the predetermined code even if he has it. This might especially happen in an emergency situation where the user is nervous, just the kind of situation in which the user would want to receive the telephone call. Also, the user has no way of knowing to wait for the answering machine to leave a message.
Another attempt was made in U.S. Pat. No. 3,514,548 to Demeo. This device permitted normal usage of a telephone, however, it did not allow incoming calls to be annunciated unless the caller dialed an appropriate supplemental code number. The problems with this device are even worse than those of Castro. If the caller does not have the code number, the caller is completely locked-out, and cannot get through to the called party at all. In addition, it is likely that Demeo would occasionally erroneously set off the annunciator during the making of outgoing calls.
U.S. Pat. No. 4,802,202 to Takahashi operates in conjunction with an answering machine, the answering machine being configured to ask for the user's telephone number. When the user enters his telephone number, Takahashi compares it against one of a plurality of prestored numbers to decide whether the call will be accepted. This obviously has a number of drawbacks including requiring a large amount of memory and also requiring the user to store many telephone numbers. A mistake in storing the telephone number will cause a called party to be avoided.
U.S. Pat. No. 4,584,434 also provides an outgoing message indicating that a predetermined code should be entered. However, this number is only used to route the operation through different lines in the installed location.
Other less applicable attempted solutions are found in U.S. Pat. Nos. 4,546,213; 4,266,098; 3,654,396; 4,345,113; 4,393,278; 4,639,552; 4,420,656; 3,902,016; 3,936,617; 4,006,316; and 4,827,501.